Process of refining fatty oils.



UNITED STATES PATENT OFFICE.

MARTIN EKENBERG, OF GGTEBORG, SWEDEN, ASSIGNOR TO THE AKTIEBO- LAGE'I GOTEBORGS OLJERAFFINERI, OF SAME PLACE.

PROCESS OF REFINING FATTY OILS.

SPECIFICATION forming part of Letters Patent No. 642,741, dated February 6,1900. 7

Application filed January 18, 1890.

To all whom it may concern:

Be it known that I, MARTIN EKENBERG, doctor of philosophy and engineer, a subject of the King of Sweden and Norway, and a resident of Hamngatan 18., Goteborg, Sweden, have invented certain new and useful Improvements in the Method of Refining Oils, of which the following is a specification.

In the refinement of fatty oils, more especially in removing free fatty acids from such oils, caustic alkalies are at present used either dissolved in water or mixed with pulverized substances, said caustic alkalies being as a rule added in such quantity that a neutralization of the fatty acids isjust accomplished.

- When oils in large quantities are to be refined at once, 'it is, however, found difficult to separate the soaps formed by the refining agent and the fatty acids of the oil. Minor quantities of fatty acids-say 0.2 to one per cent, by weight-can be removed quite easily in the usual manner; but when the percent:

age is greater-for instance, four to five per cent-the soaps, as a rule, become so slimy that it is only with the greatest diificulty that they can be separated from the oil. This depends partly on the fact that strong alkaline soaps are produced when refining in the manner hitherto used. Moreover, in the case of some oils the separation is made more diflicult from the fact that the neutral oil is capable of physically dissolving the soaps. The said difliculties of the refining process are removed by employing the present method, which consists in adding a substance which makes the soaps firm and prevents them from being dissolved in the oil. This substance is glycerin, which only need be added in quantities of, say, from 0.1 to 0.6 per cent. of the weight of oil, depending on the percentage of fatty acids inthe oil, always in such quantity, however, that the soaps will contain glycerin to the amount of from five to ten per cent of their weight. The glycerin also communicates to the soaps the property of absorbing in a higher degree than before coloring-matters and other impurities in the oil, which impurities are precipitated with the soaps.

The method is in practice carried out as Serial No. 702,553[ (No specimens.)

follows: A saturated solution of a hydrate of an alkali in commercial glycerin holding ten per cent. of water is prepared and added to the oil in such quantity that the fatty acids are neutralized. The mixture is subsequently heated to 100 centigrade or more while being carefully stirred, firm or compact granular and neutral soaps then separating and settling to the bottom as soon as the stirring ceases. The neutral oil may now easily be clarified by filtering. In the correspondingoo treatment with a hydrate of. an alkali alone slimy soaps are formed inmost cases, which soaps require along time to separate from the oil, or three strata are formed, the first containing oil, the second emulsion, and the third the undermost) lye. i The addition of glycerin to cheaper grades of oils, more especially those whose neutral fat in saponifying secretes a large amount of glycerin, may be effected by the saponification of a portion of said neutral fat, just suffieient to liberate the aforesaid minimum of glycerin which is absorbed by the soaps. Free glycerin is but rarely found in acidulous oils, and it is therefore necessary in the latter case to 'saponify from one to two times as much neutral fat as free fatty acid in the oil. Owing to this fact the modified method last mentioned can be applied only in cases where the soaps precipitated can be utilized to advantage. Also, in the latter case, heating to 100 centigrade or above this temperature must take place in order to cause the liberated glycerin to act, so that compact granular soaps Without any free hydrate of an alkali may separate. v

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is

1'. The herein-described method of refining fatty oils, consisting in adding glycerin and hydrates of alkalies, heating the mixture, while being stirred, to centigrade and then filtering, substantially as described.

2. The herein-described method of refining fatty oils consisting in mixing the oil with a hydrate of an alkali in sufiicient quantity to neutralize the free fatty acids present and to I secrete glycerinto an amount of at least five my name in' the presence of two subscribing per eenmof the weight pf the separated soaps, witnesses.

heating the mixture while stirring to 100 centigrade whereby glycerin and granular MARTIN EKENBERG' 5 neutral soaps are formed am the oil purified, Witnesses:

ALFR. A. Eitxs'm w,

substantially as described.

In witness whereof I have hereunto signed GUSTAF SETH. l 

